LMDE2 on a SSD, can't change scheduler to deadline

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BrunoMiranda
Level 3
Level 3
Posts: 109
Joined: Thu Jun 24, 2010 2:22 pm

LMDE2 on a SSD, can't change scheduler to deadline

Postby BrunoMiranda » Fri Apr 28, 2017 4:50 pm

Hi all,

I've put LMDE2 on a SSD. The SSD is recognized, as
/sys/block/sda/queue/rotational is reporting a '0'


Everything is fine except that I can't change scheduler to deadline at boot time.


If I type

Code: Select all

cat /sys/block/sda/queue/scheduler


I get this output:
noop deadline [cfq] bfq

(meaning cfq is enabled and deadline is not enabled but available)

If I run

Code: Select all

echo deadline >/sys/block/sda/queue/scheduler

as root, it will change the scheduler, as
cat /sys/block/sda/queue/scheduler will output
noop [deadline] cfq bfq

but after rebooting it will default back to
noop deadline [cfq] bfq


Note: If I run

Code: Select all

echo deadline >/sys/block/sda/queue/scheduler

as non-root or with sudo, I will get
bash: /sys/block/sda/queue/scheduler: Permission denied



If I add

Code: Select all

GRUB_CMDLINE_LINUX_DEFAULT="elevator=deadline quiet splash"

on /etc/default/grub and then run sudo update-grub, it still does not change the scheduler.

On /etc/rc.local I've added

Code: Select all

echo deadline >/sys/block/sda/queue/scheduler
echo 1 > /sys/block/sda/queue/iosched/fifo_batch

(above the exit 0)
and it still does nothing.

I've created a
/etc/udev/rules.d/60-ssd-scheduler.rules
having inside it

Code: Select all

# Set deadline scheduler for non-rotational disks
ACTION=="add|change", KERNEL=="sd[a-z]", TEST!="queue/rotational", ATTR{queue/scheduler}="deadline"
ACTION=="add|change", KERNEL=="sd[a-z]", ATTR{queue/rotational}=="0", ATTR{queue/scheduler}="deadline"


I've also tried

Code: Select all

sudo update-initramfs -u


But nothing has worked so far, after reboot, the system defaults back to bfq.

Notes:
- I have not installed LMDE2 on this SSD from scratch. Instead, I've restored a backup (using fsarchiver) of this system while using a HDD;
- I'm using the Liquorix Kernel (4.10.0-11.1-liquorix-amd64). Could this have an impact on this issue?


I've ran out of options and ideas. Any hints, please? Thanks!
Bye for now,
Bruno


(Always backup before you fvckup :mrgreen: )

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